Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain and tenderness to palpation at specific tender points. In addition, fibromyalgia patients often describe other symptoms such as fatigue, sleep disturbances, headache or cognitive dysfunction associated with the syndrome. The American College of Rheumatology has defined fibromyalgia as pain in all four quadrants combined with axial skeletal pain, and at least 11 of 18 tender point sites. Widespread pain must have been present for at least 3 months. Tender points, the diagnostic hallmark of fibromyalgia, are examples of hyperalgesia, thought to be due to central sensitization. Patients with fibromyalgia have quantitatively altered perception compared to pain-free patients, suggesting that people with fibromyalgia process sensory information differently, most likely due to changes in the central processing of pain at the spinal level.
Patients often report widespread pain over all parts of the body which often seems to arise in the muscles. The pain shows varying intensities that wax and wane over time, it is profound, widespread and chronic, and is often severely debilitating, having profound effects on the quality of life of the patients.
Typically, the pain is described as deep muscular aching, throbbing, twitching, stabbing and shooting pain. Neurological complaints such as numbness, tingling and burning are often present. The severity of the pain and stiffness is often worse in the morning. Aggravating factors that affect pain include cold/humid weather, non-restorative sleep, physical and mental fatigue, excessive physical activity, physical inactivity, anxiety and stress. Additionally to pain, patients commonly complain of fatigue in form of an all-encompassing exhaustion that interferes with even the simplest daily activities. Within the spectrum of symptoms are a decreased sense of energy, disturbances of sleep, problems with memory and concentration and varying degrees of anxiety and depression.
Certain other medical conditions are sometimes associated with fibromyalgia, such as tension headaches, migraine, irritable bowel syndrome, overactive bladder, pelvic pain, premenstrual tension syndrome, cold intolerance, dry eyes and mouth, anxiety, depression, ringing in the ears, dizziness, vision problems and others. Patients with established rheumatoid arthritis, lupus (SLE) and Sjogren's syndrome often develop fibromyalgia symptoms during the course of their disease.
The complexity of the syndrome, with multiple and highly diverse symptoms described by the patients has meant that effective and long-term relief, above all of the pain, has proved elusive. Common analgesics have limited effectiveness, especially over the long-term.